KR930006582B1 - Data reproducing device for floppy disk device - Google Patents

Abstract

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Description

A method and apparatus for adjusting a reproduction signal from a recording medium.

1A and B are diagrams showing a reproduction signal and its differential signal in the in-plane recording method.

2 is a diagram showing a configuration of the apparatus of the embodiment of the present invention.

3 is a diagram showing signal waveforms obtained at each part of the apparatus of the embodiment;

4A to 4C show a first embodiment showing a reproduction signal, its derivative signal, and a correction differential signal in the modified recording method.

5 is a schematic structural diagram of a recording medium.

Fig. 6 is a diagram showing M-H loops in the vertical direction of the recording medium.

7a and b show the amplitude and phase characteristics of a heel belt filter.

8A and 8B show amplitude and phase characteristics of the LCR series resonant circuit of the apparatus of this embodiment.

9A to 9C show a second embodiment showing a reproduction signal, its derivative signal, and a correction differential signal in the vertical recording method.

* Explanation of symbols for main parts of the drawings

10: recording medium 10a: magnetic medium

10b: base film 11: head

12 Preamplifier 13 Low Pass Filter (LPF)

14 LCR series resonant circuit 15 bit detection circuit

15a: Differential Circuit 15b: Zero Cross Detection Circuit

15c: pulse shaping circuit 16: switch

The present invention relates to a method and apparatus for adjusting a reproduction signal from a recording medium.

Conventionally, in the floppy disk device, an in-plane recording method or a vertical recording method has been used as a method of magnetically recording data on a recording medium. In particular, the vertical recording method is suitable for the high density recording mode.

By the way, in the floppy disk device, when the data recorded on the recording medium is read out by the head, a bit detection circuit is provided which generates a pulse signal inverted at the peak point of the reproduction signal detected by the head. The bit detection circuit is composed of a differential circuit for differentiating a reproduction signal, a zero cross detection circuit for generating a pulse signal inverted at the zero cross point of the differentiated reproduction signal, and a pulse shaping circuit for pulse shaping the generated pulse signal.

When data is being recorded on the recording medium by the in-plane recording method, the reproduction signal (see Fig. 1A) detected from the recording medium by the head is differentiated by the differential circuit, thereby resulting in the differential signal as shown in Fig. 1B. Is obtained. Each peak point of the reproduction signal shown in FIG. 1A corresponds to the zero cross point of the differential signal shown in FIG. 1B.

The pulse signal rising or falling at the zero cross point of the differential signal obtained in the differential circuit is generated by the zero cross detection circuit and the pulse signal by the zero cross detection circuit, and shaped by the pulse shaping circuit. The shaped pulse signal is used as a read pulse signal.

When data is being recorded on the recording medium by the vertical recording method, the reproduction signal detected from the recording medium by the head is shifted in phase compared with the reproduction signal detected by the recording medium in the above-mentioned in-plane recording method. It becomes a waveform. Therefore, in the case of reading data recorded by the vertical recording method from the recording medium, the in-plane recording method bit detection circuit cannot obtain the differential signal corresponding to the peak position of the reproduction signal, so that the accurate read pulse signal cannot be generated.

Therefore, in order to obtain compatibility with the vertical recording method, in-plane recording method floppy disk devices, for example, phase equivalent circuits or secondary differential circuits are used (Hiroshi Okamura and Hiroshi Suzuki as an example of phase equivalent circuits). US Patent No. 4,786,989 to Mr.). However, in the phase equivalent circuit, its configuration is complicated and its adjustment is difficult. In the second derivative circuit, since signal components in the high frequency region are emphasized, noise increases, and the S / N ratio decreases.

In view of the above, there is a demand for a recording / reproducing apparatus having a simple circuit configuration and capable of generating an accurate read pulse signal based on the peak of the reproduction signal.

It is an object of the present invention to provide a method and apparatus for adjusting a reproduction signal from a recording medium.

According to the present invention, there is provided a method comprising: detecting a reproduction signal representing one of a vertical recording signal and an in-plane recording signal from a recording medium; Correcting a phase of a reproduction signal when the reproduction signal is the vertical recording signal; And generating a read pulse signal according to a peak point representing one of the detected reproduction signal and the detected reproduction signal corrected such that the phase is corrected by an LCR series resonator using a predetermined dumping factor. Recording and playback in a playback device, and a playback signal from a medium.

According to another feature of the present invention, there is provided a recording medium; Means for detecting a reproduction signal representing one of vertical recording and signal from the recording medium; Means for correcting a phase of a reproduction signal when the reproduction signal is a vertical recording signal; And means for generating a read pulse signal in accordance with the peak point of one of the reproduced signal and the corrected reproduced signal detected so that said correction means includes an LCR series resonant circuit using a predetermined dumping factor. An apparatus is provided.

Embodiments of the present invention will be described below with reference to the drawings.

2, the apparatus of the present embodiment includes a head 11, a preamplifier 12, a low pass filter (LPF) 13, an LCR series resonant circuit 14, a bit detection circuit 15, and a switch 16. It consists of.

The head 11 detects a reproduction signal from the recording medium 10 in which data is recorded, for example, by a vertical recording method.

The preamp 12 amplifies the playback signal from the head 11.

The LPF 13 removes unnecessary high frequency noise from the reproduction signal amplified by the preamplifier 12. Normally, the cutoff frequency of the LPF 13 is set to about twice the maximum frequency of the reproduction signal.

The LCR series resonant circuit 14 corrects the phase and amplitude of the reproduction signal by the vertical recording method output from the LPF 13. The peak position of the corrected reproduction signal is shifted to the peak position corresponding to the in-plane recording method.

The bit detection circuit 15 is comprised by the differential circuit 15a, the zero cross detection circuit 15b, and the pulse shaping circuit 15c. The differential circuit 15a performs a differentiation on the reproduction signal. The zero cross detection circuit 15b detects the zero cross point of the differential signal output from the differential circuit 15a and generates a rising or falling pulse signal at the detected zero cross point. The pulse shaping circuit 15c shapes the pulse signal generated by the zero cross detection circuit 15b. The shaped pulse signal is used as a read pulse signal.

The switch 16 is switched by, for example, a switching signal from a recording method determination circuit (not shown). In other words, when data is being recorded on the recording medium by the vertical recording method, the reproduction signal is corrected by the LCR linear force resonance circuit 14. On the other hand, when data is being recorded on the recording medium by the in-plane recording method, the reproduction signal is input from the switch 16 to the bit detection circuit 15 without intervening the LCR series resonant circuit 14.

Next, the operation of the apparatus according to the present embodiment will be described.

When data is read from the recording medium by the vertical recording method, the voltage corresponding to the magnetic flux from the recording medium 10 is detected by the head 11, and the LPF 13 is transmitted via the preamplifier 12 as a reproduction signal. ) Is entered.

In the LPF 13, unnecessary high frequency noise is removed from the reproduction signal output from the preamplifier 12, and the reproduction signal A shown in FIG. 13 is output from the LPF 13. That is, the reproduction signal from the recording medium by the numeric recording method is shifted in phase compared with the reproduction signal from the medium by the in-plane recording method, and is not a perfect vertical waveform, that is, when the vertical and in-plane components are mixed. It becomes an asymmetric waveform.

Here, when the reproduction signal which becomes such an asymmetric waveform is differentiated by the differential circuit 15a of the bit detection circuit 15 without intervening the LCR series resonant circuit 14, the differential signal crosses zero at the peak point of the reproduction signal. Can't get it. For example, when the reproduction signal in the vertical recording system as shown in FIG. 4A is differentiated, a differential signal as shown in FIG. 4B is obtained. The reproduction signal shown in Fig. 4A is obtained by a recording medium having a perpendicular squareness ratio of 0.8 and a material of barium ferrite indicative of magnetic properties. The vertical square ratio is represented by the residual magnetization Mr in the MH lupu (see FIG. 6) in the vertical direction of the recording medium 10 constituted by the magnetic medium 10a formed on the base film 10b as shown in FIG. It is expressed as the ratio of saturation magnetization Ms (Mr / Ms).

Here, conventionally, the amplitude and phase correction of the reproduction signal is performed by a hill belt filter having the amplitude and phase characteristics as shown in Figs. 7A and 7B. However, the circuit configuration of this hill belt filter is complicated. Therefore, in this embodiment, the amplitude and phase correction of the reproduction signal output from the LPF 13 is performed by the LCR series resonant circuit 14 having a simple circuit configuration.

The LCR series resonant circuit 14 has the amplitude and phase characteristics as shown in Figs. 8A and b by the so-called dumping effect (dumping factor (R / W) NC / L). Therefore, for example, by setting the dumping factor to 1.5 and using a band W where the amplitude is relatively flat and the phase θ is close to -90 ° C, the reproduction signal A shown in FIG. 3 is equal to the reproduction signal B shown in FIG. Are corrected together. In addition, the resonance point of the LCR series resonant circuit 14 is usually selected two to three times the highest frequency corresponding to the highest magnetization reversal.

In the frequency region above the resonance point of the LCR series resonance circuit 14, high frequency noise can be reduced.

The reproduction signal B shown in FIG. 3 output from the LCR series resonant circuit 14 is differentiated by the differential circuit 15a of the bit detection circuit 15. For example, when the reproduction signal shown in FIG. 4A is corrected and differentiated, a differential signal (see FIG. 4C) whose zero cross point corresponds to the bit position is obtained.

The differential signal obtained by the differential circuit 15a is converted into a pulse signal which rises or falls at the zero cross point of the differential signal by the zero cross detection circuit 15b. That is, the zero cross detection circuit 15b generates a pulse signal in accordance with the peak of the reproduction signal B as shown in FIG. This pulse signal is shaped by the pulse shaping circuit 15c. The shaped pulse signal C shown in FIG. 3 is used as a read pulse signal.

In addition, when the vertical angle ratio of the recording medium 10 is 0.95 (a lot of vertical components), a reproduction signal as shown in Fig. 9A is detected. Therefore, when the reproduction signal output from the LPF 13 is differentiated, a differential signal as shown in Fig. 9B is obtained. On the other hand, if the reproduction signal (see Fig. 9a) is phase and amplitude correction (dumping factor 0.9) by the LCR series resonant circuit 14 and then differentiates, the differential signal corresponding to the bit position with the zero cross point as shown in Fig. 5c. Can be obtained.

According to the present invention, in the in-plane write-type floppy disk device, the circuit configuration is simple without using a phase equivalent circuit and a second differential circuit, and the phase of the reproduction signal from the recording medium by the vertical recording method is not increased. And amplitude correction. That is, the peak position of the reproduction symbol from the recording medium by the vertical recording method can be shifted to the peak position of the reproduction signal from the recording medium by the in-plane recording method. Therefore, since an accurate read pulse signal can be generated, a reliable data read operation can be realized.

As mentioned above, although the Example of this invention was described, this invention is not limited to the said Example, A various deformation | transformation is possible within the scope of the summary of this invention.

Claims (6)

Detecting a reproduction signal representing one of the vertical recording signal and the in-plane recording signal from the recording medium; Correcting a phase of a reproduction signal when the reproduction signal is the vertical recording signal; And generating a read pulse signal according to a peak point representing one of the detected reproduction signal and the detected reproduction signal corrected such that the phase is corrected by an LCR series resonator using a predetermined dumping factor. A method of adjusting a reproduction signal from a recording medium in a recording and reproduction apparatus. The method of claim 1, wherein the generating step comprises: differentially processing the corrected reproduction signal, and generating a pulse signal according to the detected zero cross point; And forming a generated pulse signal to obtain the read signal. The method of claim 1, wherein the correcting step includes correcting amplification of the reproduced signal. Recording media; Means for detecting a reproduction signal representing one of a vertical recording signal and an in-plane recording signal from the recording medium; Means for correcting a phase of a reproduction signal when the reproduction signal is a vertical recording signal; And a means for generating a read pulse signal in accordance with the peak point of one of the detected reproduction signal and the corrected reproduction signal such that the correction means includes a series resonant circuit using a predetermined dumping factor. . 5. The apparatus according to claim 4, wherein said generating means comprises: means for differentially processing a corrected reproduction signal; Means for detecting a zero cross point from the differential processed reproduction signal; Means for generating a pulse signal according to the detected zero cross point; And means for forming a pulse signal generated to obtain the read pulse signal. 5. The recording and reproducing apparatus as claimed in claim 4, wherein the correction means includes means for correcting the amplitude of the reproduction signal.

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